Advertisers have a responsibility to their clients to disclose that they are advertising products or services to them.
But if they are not, their clients can be held liable for advertising fraud.
Advertisers are not required to reveal the identity of the ad they are showing or the type of ads they are displaying, but it is helpful to have a list of what ads are being advertised.
This helps companies monitor their advertising performance and identify advertising fraud that may be occurring.
Advertiser disclosure rules vary by country.
In the U.S., for example, advertisers are required to disclose all advertising activities they perform, whether on-site, in-person or by direct mail.
But in Europe, ad disclosures must be made only with regard to their on-screen content, such as text, images or video.
In some countries, such disclosures are optional, while others require that they be made.
Ad disclosure rules in some countries are more strict than those in other countries, but most countries require that the disclosures be made to the media outlet, which may include the website of the advertiser.
For example, in the United Kingdom, for example the Advertising Standards Authority is required to make the disclosure to the Financial Times, but not to any other news organization.
In other countries like France and Italy, the disclosure is optional.
For more information, see: Advertising disclosure rules: Which countries require disclosure of ads?